Inlet for paper-making machine



March 1957 L. HQRNBOSTEL INLET FOR PAPER-MAKING MACHINE Filed June 2, 1954 United States' Patent INLET FOR PAPER-MAKING MACHINE Lloyd Hombostel, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis, a corporation of Wisconsin Application June 2, 1954, Serial No. 433,901

1 Claim. (Cl. 92--44) This invention relates to a multiple slice-equipped inlet for paper-making machines and particularly deals with a pressure inlet having a second slice insideof a closed head box to segregate a separate pond of stock immediately behind the main slice while maintaining this pond in a continuous turbulent condition to mix the fibers just .before they pass under the main slice and to prevent the formation of dead clot-forming-areas.

Multi-slice head boxes have been provided to create stock mixing ponds immediately before depositing the stock on the forming wire-of a paper machine. However, the speeding up of modern paper machinery has required maintenance of very high levels in the stock head boxes in order that the stock can be delivered underthe last slice at a sulficiently fast rate approaching the speed of travel of the forming 'wire of the paper machine. These high levels in the head box will create enough of a head pressure to develop the desired flow rate under the last slice but have interfered with a good mixing of the stock. The use of one or more slices in advance of the last or main slice has, therefore, been adapted to create pressure drops and current flow to create turbulence. The pond areas between the slices in such installations, however, must be quite high in order to maintain the necessary head to insure high speed delivery. As a result of these high or deep .pond areas, stock in the upper portions is not'circulated at the same rate as stock in the lower portions and the fibers tend to clot and e-ven 'form crusts in the tops of the pondareas. These crusts will break loose *from time to time and will be fed under the main slice to produce defective paper.

The present invention now provides a multi-slice stock inlet wherein the pond area between the slices is maintained at a relatively low level to insure turbulence throughout its entire area regardless of the required high speed rate of flow of stock. This low level pond area is maintained under super-atmospheric pressure so that the stock behind the main slice will have the desired delivery pressure to maintain a high speed delivery rate even though it has only a low head. The current in the pond between the slices will extend throughout the height of the pond and clotting or crusting of the stock fibers will be impossible.

In order to further mix the stock fibers in the head box, it is preferred to include rectifier rolls including a submerged rectifier roll at the entrance mouth to the underside of the first slice and a pair of cooperating superimposed rectifier rolls in the head box in advance of this roll. The cooperating rolls include a submerged roll and a top roll having its bottom about level with the top level of the stock pond.

A predetermined pressure is maintained in the head box by an outlet or vent port at the desired level for the stock. This vent port will be closed when the stock level rises too high whereupon pressure in the pond will be built up to depress the level. If the stock level is too low to fully uncover the port, the pressure will be decreased so that 'ice the stock feed pump can reclaim the level. The desired level is intermediate the top and bottom of the vent port.

It is then an object of this invention to provide a multislice stock inlet which will not allow clotting or crusting of stock fibers between the slices.

Another object of the invention is to provide a pressure inlet for paper-making machines having a plurality of slices creating a turbulent pond area therebetween and equipped with a pond regulator to prevent creation of a head level where crusting or clotting of the stock can take place.

A still further object of this invention is to provide a head box for high speed paper-making machines wherein a secondary slice coacts with the main slice to provide a turbulent stock pond area and wherein air pressure on the head box prevents this area from ever reaching a depth where any portion thereof is not turbulent.

Another object of this invention is to provide a pressurized 'head box for paper-making machinery with a secondary slice to create a low level turbulent pond area for admixing stock fibers immediately in advance of the main slice.

Other and further objects of this invention will be apparent to those skilled in the art from the following detailed description of the annexed sheet of drawings which, by way of a preferred example, illustrates one embodiment of the invention.

On the drawings:

The single figure of the drawings is a longitudinal crosssectional view, with parts in elevation and with parts diagrammatically illustrated, of a multi-slice head box according to this invention.

As shown on the drawings:

The head box 10 of this invention, includes a bottom wall 11, a back wall 12, side walls such as 13, a top wall 14, and a front wall 15. The bottom wall 11 has an apron portion 16 overlying a breast roll 17 on which a Fourdrinier forming wire 18 is trained. Stock from a suitable pump is supplied to the interior chamber 19 defined by the walls It to 15 through a conduit 20 from a suitable pump (not shown). The conduit opens into the bottom of the chamber 1? and supplies a pond .P of

stock to the chamber. A manhole 21 is provided in the top wall 14 and is closed by a cover 22 suitably locked in position in airtight relation with the top by means of a screw clamp 23. Air under pressure is supplied to the chamber 19 through a conduit 24 having a valve 25 therein for regulating the rate of air flow. The conduit 24 is in the top wall 14 of the head box.

An outlet port 25 is provided in a side wall 13 of the head box at a level to maintain the desired level L for the pond P of stock. This vent 26 will be completely uncovered when the stock level drops thereby reducing the air pressure on top of the pond. In such circumstances, the stoclt conduit 24) will deliver stock at an increased rate to reclaim the lost level. The stock level will thereupon rise to partially cover the outlet 26. When the stock is fed at too great a rate so as to completely cover the outlet 26, the air pressure above the pond P will be increased to such an extent that it will offset the pressure of the pump feeding the stock to the conduit 20 whereupon the level of the stock will drop. In this way, a constant level L is alway maintained intermediate the top and bottom of the outlet 26.

A pair of rectifier rolls 27 and 28 in superimposed cooperating relation, are mounted rotatably in the chamber 19 with the roll 27 immersed in the pond P and with the roll 28 cooperating with the top of the roll 27 just above the level L for the pond P.

A primary slice or main slice 29 is mounted on the front wall 15 of the head box and is raised and lowered by means of control rods such as 30 carried in a crossarsenal bar 31 on the front wall 15. Screw rod operating handles such as 32, are provided to raise and lower the rods 30 and thereby raise and lower the slice 29 relative to the top run 18 of the forming wire. The bottom edge 15a of the front wall 15 of the head box, terminates in spaced relation above the bottom of the slice 29.

A secondary slice 33 is mounted in the chamber 19 behind the wall 15 in spaced relation from the wall 15. This slice 33 has side flanges 34 with vertical slots 35 therein receiving supporting studs 36 carried by the side walls 13. Control rods such as 37 are raised and lowered by means of adjusting screws 38 carried in the top wall 14 to raise and lower the slice 33 relative to the bottom wall 11 of the head box. The slice 33 is positioned rearwardly of the apron 16 and its bottom edge 33a is at a level above the bottom edge of the slice 29. A pond P of stock forms between the slices and this pond has a level L slightly depressed from the level L of the pond P.

A rectifier roll 39 is rotatably mounted in the chamber 19 immediately behind the secondary slice 33 and adjacent the flow mouth 40 under the edge 33a of the secondary slice to agitate the stock flowing from the pond P to the pond P.

A current of stock is created as it flows through the mouth 40 and stock from this current rises to the level L in the pond P. The entire pond P, however, is maintained under turbulent conditions so that the stock fibers cannot segregate. The stock then flows from the pond P under the slice 29.

A high speed delivery rate of flow under the slice 29 is maintained by the pressure in the chamber 19 which simultaneously acts on the ponds P and P since the top of the slice 33 is beneath the top wall 14 of the stock area and the pond P is, therefore, in full communication with the chamber 19 above both ponds.

The rapid flow through the mouth 40 coupled with the agitation created by the rectifier rolls, will produce a churning action in the pond P which will break up any stock clots. Since the level L is maintained relatively low because of the air pressure thereon, no dead area can be created on top of the pond P and no crusts of dead stock will be formed. The stock will, therefore, continue to roll throughout the entire height of the pond P and feed a thoroughly admixed stock mixture underneath the apron 29 to maintain uniform stock conditions at high delivery rates.

From the above descriptions, it should, therefore, be understood that this invention provides a simple multislice stock inlet wherein the pond of stock between the slices cannot become stagnant or develop any stock clots or crusts.

It will be understood that variations and modifications may be effected without departing from the scope of the novel concepts of this invention.

I claim as my invention:

A stock inlet for paper-making machines comprising a closed head box, means for feeding stock into the bottom of the head box, means for introducing gas under pressure above the stock in the head box, a bleeder outlet in the head box at a level desired for the pond stock whereby rise of level above the outlet will increase the gas pressure to depress the level and whereby full exposure of the outlet will decrease the gas pressure to accommodate increased level of the stock, said head box having a main slice defining an outlet to the forming area of the paper machine, a secondary slice in spaced relation behind said main slice, said secondary slice having an outlet mouth thereunder, said main and secondary slices defining a supplemental stock pond area immediately adjacent the outlet under the main slice, a rectifier roll in the head box in advance of the secondary slice, a pair of rectifier rolls in the head box in advance of said first mentioned rectifier roll, one of the rectifier rolls of said pair being completely submerged in the stock at the desired level of the stock in the head box and the other of said rectifier rolls of said pair being above the stock level to coact with the top of the lower roll, and the pressure in said head box acting on the space between the main and secondary slices to depress the level of stock in said space below a level at which stock stagnation can occur.

References Cited in the file of this patent UNITED STATES PATENTS 1,818,777 Aldrich Aug. 11, 1931 2,027,611 Niks Jan. 14, 1936 2,345,647 Witham Apr. 4, 1944 2,381,286 Hornbostel et al. Aug. 7, 1945 2,509,822 Hornbostel May 30, 1950 2,548,108 Hornbostel Apr. 10, 1951 2,550,552 Goodwillie Apr. 24, 1951 2,664,033 Hornbostel et al. Dec. 29, 1953 2,677,992. Hornbostel May 11, 1954 

